1. Field of the Invention
The present invention relates to a constant current circuit which includes an input path through which a constant current on an input side of the constant current circuit flows, and an output path through which a constant current on an output side of the constant current circuit corresponding to the constant current on the input side flows.
2. Description of the Related Art
Conventionally, a great number of various current mirror circuits have been used in a semiconductor integrated circuit. Here, some of the current mirror circuits often include, with respect to one current mirror input transistor, a plurality of current mirror output transistors which are connected on a common base to the current mirror input transistor.
Such current mirror circuits are disclosed in Japanese Patent Publications JP 2006-33523, JP H10-97332, JP H07-121256, and other publications.
When a signal is handled using a circuit having a plurality of outputs as described above, in some instances, problems such as interference or leakage of a signal at high frequencies will arise through a base line of a current mirror circuit. In particular, when a gain of a signal to be handled is high, when a MIX circuit is used, or when a signal to be handled is of high frequency, it is highly likely that the above-described problem of signal leakage will occur. Further, there may be cases where the occurrence of the above-described problem causes generation of unexpected oscillation depending on the amount of leakage or phase conditions.